Large-distance communications beyond a few meters is challenging for Terahertz (THz) signals because of high spreading loss and absorption in the media. The smart antenna concept used for RF antennas to improve the signal-to-interference/noise level can be extended to these THz antennas. Out of the two types of implementations of this concept, viz. (i) adaptive array and (ii) switched-beam antenna, this paper presents the switched-beam nanoantenna for the THz wave region. Based on the Yagi-Uda antenna concept, switched-beam graphene nanoantennas over silicon dioxide (SiO₂) substrate is proposed in this paper. In one case (Antenna-I), the antenna is able to switch the beam in ± 90º directions, whereas in the other case (Antenna-II), the switching directions are 0º, ± 90º, 180º. This pattern reconfigurability can also be observed over a frequency range leading to simultaneous pattern and frequency reconfigurable nature of the nanoantenna. The reconfigurability is obtained by changing the graphene conductivity through its chemical potential. Due to plasmonic wave propagation in graphene at THz, the proposed graphene nanoantenna resonates at a sub-wavelength scale. Design aspects and the working principle of switched-beam graphene plasmonic nanoantennas in the THz region are discussed in this paper.

对于太赫兹（THz）信号，超过几米的大距离通信具有挑战性，因为介质中的传播损耗和吸收率很高。用于RF天线以改善信号干扰/噪声水平的智能天线概念可以扩展到这些THz天线。在此概念的两种实现中，即。（i）自适应阵列和（ii）开关波束天线，本文提出了针对THz波区域的开关波束纳米天线。基于八木宇田天线概念，二氧化硅（SiO ₂）本文提出了基材。在一种情况下（Antenna-I），天线能够在±90º方向上切换波束，而在另一种情况下（Antenna-II），天线的切换方向为0º，±90º，180º。还可以在导致纳米天线的图案和频率可重构性质同时发生的频率范围内观察到这种图案可重构性。可重构性是通过改变石墨烯的电势来获得的。由于等离子波在THz处在石墨烯中的传播，因此所提出的石墨烯纳米天线在亚波长范围内产生谐振。本文讨论了太赫兹区域中的开关束石墨烯等离子纳米天线的设计方面和工作原理。